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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Mel Gorman <mel@csn.ul.ie>
Subject: Re: [PATCH 11/25] Calculate the cold parameter for allocation only once
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> GFP mask is checked for __GFP_COLD has been specified when deciding which
> end of the PCP lists to use. However, it is happening multiple times per
> allocation, at least once per zone traversed. Calculate it once.
> 
> Signed-off-by: Mel Gorman <mel@csn.ul.ie>
> ---
>  mm/page_alloc.c |   35 ++++++++++++++++++-----------------
>  1 files changed, 18 insertions(+), 17 deletions(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 1506cd5..51e1ded 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1066,11 +1066,10 @@ void split_page(struct page *page, unsigned int order)
>   */
>  static struct page *buffered_rmqueue(struct zone *preferred_zone,
>  			struct zone *zone, int order, gfp_t gfp_flags,
> -			int migratetype)
> +			int migratetype, int cold)
>  {
>  	unsigned long flags;
>  	struct page *page;
> -	int cold = !!(gfp_flags & __GFP_COLD);
>  	int cpu;

Honestly, I don't like this ;-)

It seems benefit is too small. It don't win against code ugliness, I think.